Inflicts 18,525 to 19,475 Shadow damage and increases Dread Shadows damage taken by 10%. Stacks.
Nightmare
Inflicts 63,375 to 66,625 Shadow damage and inflicts fear on enemies within 8 yards for 3 sec.
Sun Breath
Inflicts 3,900,000 to 4,100,000 Nature damage and stuns Sha enemies within 0 yards and causes Bathed in Light on allies.
Sunbeam
Tsulong is resisting the Sha and is able to shield his friends from the Dread Shadows with a Sunbeam. Standing in the Sunbeam makes the target immune to Dread Shadows, but slowly shrinks the Sunbeam.
Shadow Breath
Inflicts 136,500 to 143,500 Shadow damage and increases Shadow damage taken by 100% for 30 sec. Stacks.
Strategy
This fight is a heal the boss to full with a twist type fight. It is similar in sun phase to Valithria Dreamwalker from Icecrown Citadel. There are two phases: Day and Night. In the Night phase, the raid damages down the boss. However, in the Day phase, the raid protects him and while healing him. The boss has an energy bar, and when it hits 100, the area changes from Night to Day or vise versa. Let X be the percent remaining on the boss at the end of phase. Then 100%-X is how much the boss has going into the new phase. For example, if the raid gets the boss to 80% at the end of the Night phase, then the boss is at 20% going into the Day phase. Getting the boss to 0% in the Night phase or 100% in the Day phase ends the fight.
The fight begins in the Night phase, so I will explain that one first. The main thing to know prior to explaining each phase is if the boss is defeated by the Sha (possibly a berserk timer or the boss hits 0% in the Day phase), then he will cast Unleashed Sha Explosion. This does 6 million damage to the raid and will wipe it.
Phase 1: Night Phase
During the Night phase, the raid damages the boss. Remember that when the boss hits 0% health in this phase, the fight is over. The main mechanic of this phase is Dread Shadows. Every 2 seconds, the raid takes 30k (45k) shadow damage and gains a stacking debuff increasing shadow damage taken by 10% per stack. The raid will want to reset the stacks before they get too high.
In order to reset stacks the boss will cast Sunbeam. This spawns a beam of light at a random location. Standing in the beam removes the debuff but it shrinks as people stand in it. Therefore, the raid cannot stack in the beam and must instead use it strategically. If a player has high stacks (around 10), he/she should move into the beam to remove stacks then immediately out.
The next ability is Nightmares. The boss will select 4 players and deal 100k (250k) shadow damage and inflict a 3 second fear to everyone within 8 yards of those locations. Therefore, everyone should be 8 yards away from each other. A good rule of thumb is to reset stacks during each Nightmares.
The last ability he has in this phase is Shadow Breath. This does 200k (350k) shadow damage to everyone in a 30 yard frontal cone of the boss. As long as the boss is not facing the raid, the current main tank should be the only one hit. This also applies a stacking debuff that increases damage taken by 100% per stack for 30 seconds. This means the tanks must swap after each breath. Also, it is recommended that the second tank resets his/her stacks via the Sunbeam immediately before taunting
Phase 2: Day Phase
During the Day phase, the raid heals the boss. This is identical to Valithria Dreamwalker. If the boss hits 100% health in this phase, the fight is over. This becomes an add phase since the boss is now an ally. Each add has unique abilities that I will explain below.
Embodied Terror
Terrorize
Inflicts 10% of current health as Shadow damage, dealing a minimum of 10,000 damage.
The first add is the Embodied Terror. There are two things worth noting. First, it has the ability Terrorize. The add selects both a player and the boss. The player is inflicted with Terrorize, which does 20% (50%) of the player's current health every 2 seconds for 10 seconds. The boss is inflicted with Terrorize, which does 2% (5%) of the boss' maximum health every 2 seconds for 10 seconds. This must be dispelled. The second thing worth noting is that when the add dies, 5 Fright Spawns appear.
Fright Spawns
Fright
Inflicts 117,000 to 123,000 Shadow damage and inflicts Fear for 2 sec.
The Fright Spawn has one key ability: Fright. This does 75k (100k) shadow damage and a 2 second fear to everyone within 30 yards for 2 seconds. This means the raid needs to be 30 yards away from the adds, and the raid should burn them down as quickly as possible.
Unstable Sha
Instability
Inflicts 2,925,000 to 3,075,000 Shadow damage to Tsulong.
The third type of add is the Unstable Sha. This add spawns near the boss and moves towards it. The raid must kill the add before it reaches the boss. If successful, the add will inflict the boss with Instability. This does 2.5 million (10 million) damage to the boss. The other thing this add has is , which does 150k (220k) shadow damage to a random player, but it costs the add 15% of its maximum health. The raid should let the cast go off to kill the add faster.
The last thing in this phase is the boss will try to help the raid by casting Sun Breath. This does 2 million (4 million) damage to all Sha in a 60 yard cone in front of the boss. With that said, it is recommended that any possible Sha adds should be tanked in front of the boss. Also, any player hit by the breath gains a buff called Bathed in Light. This restores 25% of the player's total mana and increases healing done by 500% for 15 seconds. Obviously, all healers should be in front of the boss during the entire phase.